Ossa Mar Front Brake

[scot taco]

Is there anyway to get the front brake to work, or better yet,has anyone had any luck fitting a different front wheel? If so what was it from? It would be nice to fit a TY front wheel.

[lineaway]

The front brake never worked well from new. From a vintage stand point, butchering the front for a lousy ty is the 8 th sin. Problem riders now a days do not understand vintage bike set up. The bikes need to be jetted well, and we ran no idle. With it not having an idle(remember no clutch was used)once the throttle was closed the heavy flywheel kept it chugging along at very slow rpms and only took just a crack of the throttle to start hitting again. With this set up it did not take all that mauch braking to slowly work your way down even the steepest drops.

There are several methods to get a brake better, but you need to start off with fresh pads, new cable and a quality lever before anything else.

[woody]

Find somewhere that can reline your shoes with decent material. I don't know what shoes you have available over in the US but the over then counter shoes here are pretty poor.

I use a local lining company that have material that gives good results in oily conditions or under water (not sure what the original application is that uses this material but it's nothing to do with trials bikes...)

It's not perfect but it's much better than the shoes available from retail. We have them extra thick and then machine them down to fit.

The front brake in my two MARs is reasonably good and comparable to most other drum brakes on trials bikes.

Of course, if your hub is worn or oval, there's not much you can do with shoes without skimming or relining it.

[feetupfun]

Also you may not have enough clearance in the backing plate axle hole to allow the shoes to be centered in the drum

[scot taco]

Thanks to all for the input.Woody,what type of shop did the machining of the linings? I have a new set that are to big to fit the drum,but wasn,t sure who to ask about turning them down or if that was even an option.

I will have to look at what brand they are when I go back out,but I do like the idea of having them re-lined with a better material and then machined to fit.

Lineaway,I still have the old pads as the new ones didn,t fit,a new cable and new amal levers.The backing plate was disassembled,cleaned and lubed-so I think I,m on the right track.I should add that this isn,t a MAR,but the older Plonker that came before it,but it looks to be the same front wheel.The carb is jetted pretty good and she will run right down to a stall and pick back up cleanly.The problem in my area is there are no true vintage trials.They just have a class for it in my district (17) and we ride the modern intermediate line.

feetupfun,thats a good call.I always try to put it back together correctly to try and center the shoes and not bind the forks,but I never thought about that.

Edited December 21, 2013 by scot taco

[woody]

You just need someone with a lathe to do the shoes for you. Just fit the linings to the brake plate, put it in the chuck and turn the linings down until they fit into the hub.

I think the front hub may be slightly bigger in your bike than the MAR, the rear definitely is as the MAR had the same hub size front/rear

[lineaway]

I could ride a MAR in your sections easily, but a Plonker could be a handful! Good Luck. Any way I would try modern perches and levers as they do offer better leverage.